What is CVE-2026-21999?

CVE-2026-21999 is a medium-severity vulnerability in Oracle XML Database, classified under Information Disclosure. CVSS score: 5.3/10. Published 2026-04-21.

How severe is CVE-2026-21999?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Information disclosure in Oracle XML Database

CVE-2026-21999

Vulnerability in the XML Database component of Oracle Database Server. Supported versions that are affected are 23.4.0-23.26.1. Difficult to exploit vulnerability allows unauthenticated attacker with network access via HTTPS to compromise XML Database. Successful attacks require human interaction from a person other than the attacker. Successful attacks of this vulnerability can result in unauthorized access to critical data or complete access to all XML Database accessible data. CVSS 3.1 Base Score 5.3 (Confidentiality impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N).

Vulnerability class: Information Disclosure

Published 2026-04-21 · last modified 2026-10-26.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.002 (15.6th percentile), scored 2026-11-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 16th percentile — 15.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000

Affected products

Oracle XML Database
Oracle Corporation Database Server — versions 23.4.0

Weakness classification (CWE)

CWE-200 — Information Disclosure

References

www.oracle.com/security-alerts/cpuapr2026.html (vendor-advisory, Patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-21999?: CVE-2026-21999 is a medium-severity vulnerability in Oracle XML Database, classified under Information Disclosure. CVSS score: 5.3/10. Published 2026-04-21.
How severe is CVE-2026-21999?: Medium severity. CVSS v3 base score is 5.3 out of 10.